Probe makes safe landing on Saturn moon

WASHINGTON—Humankind stretched its legs farther into the solar system early Friday, and in a historic first kicked up some dirt on another planet's moon. The result: eerily Earthlike photos of Saturn's moon Titan.

The European space probe Huygens landed human technology on a cosmic surface farther from Earth than ever before, revealing a moon with recognizable features such as river channels, hills and shorelines.

Huygens, a 700-pound wok-shaped lander, lived hours longer than engineers expected, and is beginning to provide a peek at what Earth could have looked like in its infancy.

More discoveries are likely as scientists sort through the 350 images that started streaming late Friday to mission control in Darmstadt, Germany. The best images are expected to debut Saturday.

"The scientific data that we are collecting now shall unveil the secrets of this new world," said Jean-Jacques Dordain, the director general of the European Space Agency.

Huygens hitched a ride on NASA's $3 billion Cassini probe, which will spend four more years circling Saturn.

The Darmstadt control center was silent in awe as the first black-and-white images appeared from the descending Huygens. They showed "things that look very much like drainage channels," said Martin Tomasko, a University of Arizona professor who was in charge of one of the cameras.

"The reason it looks like Earth is because you're seeing things that kind of look like river channels, look like hills," Cassini imaging-team scientist Torrence Johnson told Knight Ridder in an interview.

The initial images, taken from 10 miles above the ground, looked as if they could have been taken on Earth. That makes them unlike images of other planets and moons that show stark deserts and craters, Johnson said. Titan looks like a planet alive—geologically.

"It's a real frigid version of an active body, but it's active" Johnson said.

NASA science chief Al Diaz said, "All of our preconceptions that all of these planets were simply static and frigid places. Watching now, again, seeing a planet emerge that has got dynamics and complexities ... is just amazing."

What's most intriguing about the early images is the obvious effects of erosion from some kind of liquid. On a moon with a surface temperature nearly 300 degrees below zero, water didn't cause the erosion, but liquid methane, ethane or other hydrocarbons probably did, Johnson said.

Another photo shows Titan's surface, described in NASA's caption as having "ice blocks strewn around."

Scientists theorize that Titan today is somewhat similar to Earth 4 billion years ago and that chemical reactions going on there resemble what they think gave birth to life here.

Think of it as "an opportunity to go look at Earth in deep freeze and go study," NASA Cassini program manager Bob Mitchell said in a telephone interview.

Titan is the only moon in our solar system with clouds and a planetlike atmosphere. That opaque orange atmosphere is 95 percent nitrogen with the rest methane, cyanide and other hydrocarbons. Ten times thicker than Earth's, Titan's atmosphere blocked all efforts until now to peek into a world that has fascinated scientists for hundreds of years and science fiction authors for decades.

Just by landing, scientists learned a crucial new fact about Titan: It has a solid surface. Until Friday, some scientists thought the surface might have been liquid methane.

"We know there's a surface; we know that we hit something and stopped," Mitchell said.

Before landing, Huygens plummeted for 147 minutes through the atmosphere of Saturn's biggest moon. It came to a parachute-assisted rest on Titan's surface at 7:34 a.m. EST. Moments after landing, it began beaming images back up to Cassini, which forwarded them to Earth.

Huygens—pronounced HIGH-guns and named after the Dutch astronomer who first spotted Titan in 1655—continued to beam data to Cassini for more than 2.5 hours. By then Cassini had moved away and couldn't collect more data.

Huygens did experience one glitch: One of two devices to transmit data didn't work.

Cassini's seven-year trip to Saturn, while a challenge, wasn't new to NASA. But landing Huygens—especially penetrating the thick atmosphere without burning up—"was considerably more difficult," Mitchell said.

"In terms of both an engineering accomplishment and scientific accomplishment, this is easily the high point of the mission," he said Friday.

Within several minutes of its landing, all of Huygens' data—mostly measurements of Titan's strange atmosphere—had been sent to Cassini, Mitchell said. Cassini, once turned away and heading back on its usual orbit of Saturn, won't be back to Titan for 32 days. By then, Huygens' batteries will be long dead.